A Microsystem with Varying-Length Electrode Arrays for Auditory Nerve Prostheses

This paper reports the design, fabrication and simulation of a novel array of micromachined electrodes with different lengths for use in auditory nerve prostheses. A 10times10 array is created in a 1 mm ² on silicon with bulk micromachining technology. The electrode lengths vary from 200 mum to 400 mum. This design could provide access to most fascicles within the auditory nerve and thus allow stimulation of a broad tonotopic range within the nerve fiber. A multichannel ultra-low power circuit is also designed, fabricated, and tested for neural signal recording. The chip is fabricated in 0.5 mum AMI CMOS technology with a die size of 1.5 mmtimes1.5 mm. The total power consumption is less than 100 muW